Genetics

Patellar Luxation

In normally developed legs, the bones of the femur or upper leg bone, and the tibia, lower leg bone, are straight. The high muscles are aligned with the bones and run from the hip joints in a straight line, very much like the strings of a violin, over the knee joint, attach to the patella or knee cap, then attach to the tibia crest. The only way that a dog with straight legs and good muscle can have a slipped stifle is from a trauma or injury in which the muscles and tissues holding the knee caps in place are accidentally torn or weakened. Many bad stifles are caused by allowing young dogs too much freedom to jump or play on slippery floor. Such stifles are not inherited. To be inherited the thigh bones must bow outward. There is no way that the taut muscles of the leg can follow the curve of a bone. Instead it pulls to the inside of the legs and the patella's are luxated or slipped to the inside of the legs from their correct position. It is the bowed legs that are inherited and cause subluxation of the patella's rather than the subluxed patella that is inherited. When a dog with straight legs runs, the action of the muscles is free and they pull in a straight line over the center of the knee caps, but when the legs are bowed and the dog runs, the knee caps are pulled to the inside of the legs. In so doing, the supporting tissues around the Patella's are weakened and become torn so that the patella's are free to slip in and out anytime there is the least amount of angular pull.

Genetically Speaking

Homozygous & Heterozygous

The meaning of these two unfamiliar words that are part of the genetic vocabulary. Everyone today knows the meaning of the words homosexual and heterosexual. Let's define them. A homosexual prefers a member of the same sex, while a heterosexual prefers one of the opposite sex. You know that a zygote is a fertilized cell or the union of two sex cells, the sperm and the ovum, and you know that in this cell lie the 39 pairs of chromosomes and the thousands of genes that contribute to the development and manifestation of specific traits in the living animal, the dog. Now you should understand the meaning of homozygous and heterozygous. Homozygous means two of the same genes or an identical pair. It is what Mendel called Pure and his pure plants bred true for the characteristics that the pair influenced. Heterozygous means two differing genes in a pair or mixed genes, one of each kind, and is hat Mendel called a hybrid. His hybrid plants were impure and did not breed true. The pairs of homozygous genes may be either dominant or recessive, but the heterozygous genes must be one of each, one dominant and one recessive.

Genotype and Phenotype

These are the other two most important words in a breeder's vocabulary and, unless a breeder recognizes that every animal is in reality two different beings, he cannot breed with any degree of skill. What an animal looks like on the outside, its physical appearance, is its Phenotype. It is the phenomenon of how certain genes came together to create its appearance. What a dog looks like on the inside is its Genotype or the make-up of the genes responsible for all the good and bad qualities that can be seen in its phenotype and many others that remain hidden within. The Genotype is the blueprint of every trait it inherited from its ancestors and can pass along to future generations. We must constantly remind ourselves that how a dog looks or acts or moves may be no guide whatsoever to the qualities it can pass on to its offspring.

"Physical Compensation is the Foundation Rock

upon which all enduring worth must be Built "

Advantages of Line Breeding

The results obtained by this system of breeding can more certainly be predicted than the average breeder realizes. Few indeed are the dog fanciers who do more than mate a bitch to a dog Hoping for results that there is no scientific reason to expect. When by good fortune one or two above average offspring do appear, they have nothing behind them upon which to base an expectation that they will pass on their desirable traits. On the other hand, when such superior offspring are produced by line breeding, and an improvement is shown, it is backed up by the most powerful hereditary influence obtainable because of the simplicity and strength of the ancestry. If the Selection of this ancestry has been good, the "pulls" are all in the same direction.

Disadvantages of Line Breeding

Selection by pedigrees alone, without consideration being given to the physical traits of the mating pair, is the chief danger in this system of breeding. A line bred pedigree is valuable or dangerous in exact proposition as the individuals have been selected. Line breeding does not replace selection but, on the contrary, demands the most discriminating of choices within the line. If the breeder selects by pedigree, and without consideration to physical compensation, undoubtedly dogs with notable faults will result, and thus line breeding will insure failure quicker and more certainly than will any other known system of breeding. No other breeding plan has ever brought about the good results of line breeding, and no other system will ever be so powerful in the production of consistently good animals, and this with the greatest certainty year after year. The principal requirement is not to abandon individual selection. A pedigree is a guarantee of bloodlines, a record of the blood of ancestors within which breeding operations and selection may, with confidence be confined. The word "confined" is used advisedly for, after line breeding has been practiced for a few generations, the end results is the development of what is in effect of pure breed - a breed within a breed, so to speak. When that has occurred, any attempt to introduce "cold" blood is likely to result in the penalties of hybridization. The departure from line breeding is a kind of "crossing" in a small degree, for when the blood of line bred animals becomes intensified they assume all the attributes of a distinct strain, which in truth they are, and they will likely behave as such for a long time.

Advantages of Inbreeding

A large proportion of pre potent sires have been inbred or at least closely line bred. An inbred dog is, of course, enormously more pre potent than one who has outcrops breeding. Its half of the ancestry having a great deal of identical blood is almost certain to dominate the offspring when mated to one of the opposite sex having an "open" pedigree. (An "open" pedigree is one in which there does not appear the name of any one dog more than once in perhaps several generations.) Inbreeding is therefore recognized as the most influential of all breeding plans or systems, supplying the simplest of all pedigrees - an advantage when we recognize the laws of inheritance. It is all that line breeding is and more. When using either system it must be again be cautioned that careful Selection must continually be made, both as to physical compensation and vigor and fertility. In conclusion no other method of breeding equals this for intensifying bloodlines, making the best use of exceptional individuals, and in building a strain within a breed.

Disadvantages of Inbreeding

Although the doubling up and intensifying of characteristics by this method of breeding insures results that are more probable than possible and, if continued long enough, are a certainty, it works the same for one trait as another, both good and bad. If affects all characteristics of the animals involved. That is why, unless a breeder knows a good individual of his breed when he sees one, or possesses the right stock to start with, inbreeding can bring disaster. On the other hand, when the opposite is true, the most strikingly successful results can be obtained.

Recessive Vs Dominant

By the intelligent application of genetic principles we can choose to reinforce traits that we consider desirable and reduce the incidence of those we feel are detrimental by trying to ensure that our litters are as homozygous as possible for those alleles that produce the desired effect. An animal that has a high percentage of its genes in the homozygous state will pass those features on with a great deal of consistency, and is said to be "pre potent" for those features.

Summary:

Dominant Traits

1. Do not skip generations

2. Generally affect a large # of progeny

3. Only animals showing the trait carry it

4. There is less danger of continuing undesirable- desirable traits

5. The trait may come from just one parent

Recessive Traits

1. The trait may skip one or more generations

2. Generally affect a small # of progeny

3. Only animals homozygous for the trait exhibit it

4. Heterozygous animals can only be determined by mating, so there is more danger of continuing undesirable traits

5. The trait, when seen must come from both parents

Puppy Evaluation

1. Tail-set

a. high b. low

2. Eyes

a. almond b. round c. bulgy

3. Head

a. wedge b. dome

4. Legs

a. angulation b. straight c. toes in d. toes out

5. Stifles

a. sound b. slipping c. out

6. Ears

a. tiny b. set high c. low d. big

7. Coat

a. coarse b. stands off c. flat d. sparse

8. Length

a. cobby b. long backed

9. Ch's in Pedigree

a. 50%+ b. less than 50%

10. Personality

a. extrovert b. shy

11. Color

a. good b. mis-mark c. recessive

12. Line bred

a. yes b. no c. little

13. Weight

a. 3-5 b. 6-7 c. over 7 d. under 3

14. Throws better

a. yes b. no

15. Pasterns

a. up on toe b. down

16. Skeletal

a. strong b. shallow c. out at elbows d. cow hock

17. Bite

a. scissors b. undershot c. overshot d. reverse

18. Top line

a. straight b. roach c. swayback

19. Muzzle

a. good stop b. slight stop c. no stop

20. Nose

a. short b. long c. medium

21. Pigment

a. black b. self-color c. poor d. recessive

22. Shoulder

a. straight w/layback (head high) b. forward head (looks long)

23. Gait

a. smooth b. loose c. hackney

24. Feet

a. round b. hare feet c. splayed

25. Neck

a. short b. long

26. Balance

a. yes b. no

27. Heart

a. good b. hereditary defects

28. Fontanelle

a. closed b. open

29. Ribs

a. well b. slab-sided c. barrel chested d. too narrow

_Keep _Show Quality _Brood

_Sell _Breedable_ Pet spay/Neuter

Genetics 11

All characteristics both good and bad exist in various degrees in different dogs. It is vital that you know what dogs are in your pedigree and what they have produced to ensure recessive and dominant faults & virtues so that you have an idea where each came from and who carries it. It is a process of elimination. One wishes in his mating to secure and retain the desirable characteristics, and it is easily demonstrated that this can best be accomplished by inbreeding and, to a lesser degree by line-breeding. It is also easy to show that, by using the same methods of breeding, the lowest intensity of undesirable characteristics is attainable. Results are entirely dependent upon "Selection"

Genetically Dominant

and Recessive Traits

Dominant Recessive

Long Head****************************Short Head

Large Or Long ears**************Small or Short ears

Low set ears**********************High set ears

Wide ear leather******************Narrow ear leather

Coarse skull***********************Fine skull

Short foreface*********************Long foreface

Erect ears ************************Drop of tipped ears

Dark eye***************************Light eye

Normal eye ************************Large bulging eyes

Brown eye*************************Blue eye

Wire, short or curly coat **********Smooth long or straight coat

Poor lay back **********************Good lay back

Poorly angulated stifle************Well angulated stifle

High set tail************************Low set tail

Heavy bone************************Light Bone

Deep chest************************Shallow chest

Straight topline********************Sway back

Good spring of rib*****************Poor spring of rib

Short stifle**************************Long stifle

Light pigment**********************Dark pigment

Normal hearing********************Deafness

Good eyesight*********************Night blindness

Good eye pigment****************Wall eyes

Self-color***************************Parti-Color

Black nose*************************Dudley nose

Good mouth************************Overshot or undershot

Normal palate**********************Cleft palate

Normal lip**************************Hair lip

Straight tail*************************Kinked or bent tail


	Genetics Patellar Luxation In normally developed legs, the bones of the femur or upper leg bone, and the tibia, lower leg bone, are straight. The high muscles are aligned with the bones and run from the hip joints in a straight line, very much like the strings of a violin, over the knee joint, attach to the patella or knee cap, then attach to the tibia crest. The only way that a dog with straight legs and good muscle can have a slipped stifle is from a trauma or injury in which the muscles and tissues holding the knee caps in place are accidentally torn or weakened. Many bad stifles are caused by allowing young dogs too much freedom to jump or play on slippery floor. Such stifles are not inherited. To be inherited the thigh bones must bow outward. There is no way that the taut muscles of the leg can follow the curve of a bone. Instead it pulls to the inside of the legs and the patella's are luxated or slipped to the inside of the legs from their correct position. It is the bowed legs that are inherited and cause subluxation of the patella's rather than the subluxed patella that is inherited. When a dog with straight legs runs, the action of the muscles is free and they pull in a straight line over the center of the knee caps, but when the legs are bowed and the dog runs, the knee caps are pulled to the inside of the legs. In so doing, the supporting tissues around the Patella's are weakened and become torn so that the patella's are free to slip in and out anytime there is the least amount of angular pull. Genetically Speaking Homozygous & Heterozygous The meaning of these two unfamiliar words that are part of the genetic vocabulary. Everyone today knows the meaning of the words homosexual and heterosexual. Let's define them. A homosexual prefers a member of the same sex, while a heterosexual prefers one of the opposite sex. You know that a zygote is a fertilized cell or the union of two sex cells, the sperm and the ovum, and you know that in this cell lie the 39 pairs of chromosomes and the thousands of genes that contribute to the development and manifestation of specific traits in the living animal, the dog. Now you should understand the meaning of homozygous and heterozygous. Homozygous means two of the same genes or an identical pair. It is what Mendel called Pure and his pure plants bred true for the characteristics that the pair influenced. Heterozygous means two differing genes in a pair or mixed genes, one of each kind, and is hat Mendel called a hybrid. His hybrid plants were impure and did not breed true. The pairs of homozygous genes may be either dominant or recessive, but the heterozygous genes must be one of each, one dominant and one recessive. Genotype and Phenotype These are the other two most important words in a breeder's vocabulary and, unless a breeder recognizes that every animal is in reality two different beings, he cannot breed with any degree of skill. What an animal looks like on the outside, its physical appearance, is its Phenotype. It is the phenomenon of how certain genes came together to create its appearance. What a dog looks like on the inside is its Genotype or the make-up of the genes responsible for all the good and bad qualities that can be seen in its phenotype and many others that remain hidden within. The Genotype is the blueprint of every trait it inherited from its ancestors and can pass along to future generations. We must constantly remind ourselves that how a dog looks or acts or moves may be no guide whatsoever to the qualities it can pass on to its offspring. "Physical Compensation is the Foundation Rock upon which all enduring worth must be Built " Advantages of Line Breeding The results obtained by this system of breeding can more certainly be predicted than the average breeder realizes. Few indeed are the dog fanciers who do more than mate a bitch to a dog Hoping for results that there is no scientific reason to expect. When by good fortune one or two above average offspring do appear, they have nothing behind them upon which to base an expectation that they will pass on their desirable traits. On the other hand, when such superior offspring are produced by line breeding, and an improvement is shown, it is backed up by the most powerful hereditary influence obtainable because of the simplicity and strength of the ancestry. If the Selection of this ancestry has been good, the "pulls" are all in the same direction. Disadvantages of Line Breeding Selection by pedigrees alone, without consideration being given to the physical traits of the mating pair, is the chief danger in this system of breeding. A line bred pedigree is valuable or dangerous in exact proposition as the individuals have been selected. Line breeding does not replace selection but, on the contrary, demands the most discriminating of choices within the line. If the breeder selects by pedigree, and without consideration to physical compensation, undoubtedly dogs with notable faults will result, and thus line breeding will insure failure quicker and more certainly than will any other known system of breeding. No other breeding plan has ever brought about the good results of line breeding, and no other system will ever be so powerful in the production of consistently good animals, and this with the greatest certainty year after year. The principal requirement is not to abandon individual selection. A pedigree is a guarantee of bloodlines, a record of the blood of ancestors within which breeding operations and selection may, with confidence be confined. The word "confined" is used advisedly for, after line breeding has been practiced for a few generations, the end results is the development of what is in effect of pure breed - a breed within a breed, so to speak. When that has occurred, any attempt to introduce "cold" blood is likely to result in the penalties of hybridization. The departure from line breeding is a kind of "crossing" in a small degree, for when the blood of line bred animals becomes intensified they assume all the attributes of a distinct strain, which in truth they are, and they will likely behave as such for a long time. Advantages of Inbreeding A large proportion of pre potent sires have been inbred or at least closely line bred. An inbred dog is, of course, enormously more pre potent than one who has outcrops breeding. Its half of the ancestry having a great deal of identical blood is almost certain to dominate the offspring when mated to one of the opposite sex having an "open" pedigree. (An "open" pedigree is one in which there does not appear the name of any one dog more than once in perhaps several generations.) Inbreeding is therefore recognized as the most influential of all breeding plans or systems, supplying the simplest of all pedigrees - an advantage when we recognize the laws of inheritance. It is all that line breeding is and more. When using either system it must be again be cautioned that careful Selection must continually be made, both as to physical compensation and vigor and fertility. In conclusion no other method of breeding equals this for intensifying bloodlines, making the best use of exceptional individuals, and in building a strain within a breed. Disadvantages of Inbreeding Although the doubling up and intensifying of characteristics by this method of breeding insures results that are more probable than possible and, if continued long enough, are a certainty, it works the same for one trait as another, both good and bad. If affects all characteristics of the animals involved. That is why, unless a breeder knows a good individual of his breed when he sees one, or possesses the right stock to start with, inbreeding can bring disaster. On the other hand, when the opposite is true, the most strikingly successful results can be obtained. Recessive Vs Dominant By the intelligent application of genetic principles we can choose to reinforce traits that we consider desirable and reduce the incidence of those we feel are detrimental by trying to ensure that our litters are as homozygous as possible for those alleles that produce the desired effect. An animal that has a high percentage of its genes in the homozygous state will pass those features on with a great deal of consistency, and is said to be "pre potent" for those features. Summary: Dominant Traits 1. Do not skip generations 2. Generally affect a large # of progeny 3. Only animals showing the trait carry it 4. There is less danger of continuing undesirable- desirable traits 5. The trait may come from just one parent Recessive Traits 1. The trait may skip one or more generations 2. Generally affect a small # of progeny 3. Only animals homozygous for the trait exhibit it 4. Heterozygous animals can only be determined by mating, so there is more danger of continuing undesirable traits 5. The trait, when seen must come from both parents Puppy Evaluation 1. Tail-set a. high b. low 2. Eyes a. almond b. round c. bulgy 3. Head a. wedge b. dome 4. Legs a. angulation b. straight c. toes in d. toes out 5. Stifles a. sound b. slipping c. out 6. Ears a. tiny b. set high c. low d. big 7. Coat a. coarse b. stands off c. flat d. sparse 8. Length a. cobby b. long backed 9. Ch's in Pedigree a. 50%+ b. less than 50% 10. Personality a. extrovert b. shy 11. Color a. good b. mis-mark c. recessive 12. Line bred a. yes b. no c. little 13. Weight a. 3-5 b. 6-7 c. over 7 d. under 3 14. Throws better a. yes b. no 15. Pasterns a. up on toe b. down 16. Skeletal a. strong b. shallow c. out at elbows d. cow hock 17. Bite a. scissors b. undershot c. overshot d. reverse 18. Top line a. straight b. roach c. swayback 19. Muzzle a. good stop b. slight stop c. no stop 20. Nose a. short b. long c. medium 21. Pigment a. black b. self-color c. poor d. recessive 22. Shoulder a. straight w/layback (head high) b. forward head (looks long) 23. Gait a. smooth b. loose c. hackney 24. Feet a. round b. hare feet c. splayed 25. Neck a. short b. long 26. Balance a. yes b. no 27. Heart a. good b. hereditary defects 28. Fontanelle a. closed b. open 29. Ribs a. well b. slab-sided c. barrel chested d. too narrow _Keep _Show Quality _Brood _Sell _Breedable_ Pet spay/Neuter Genetics 11 All characteristics both good and bad exist in various degrees in different dogs. It is vital that you know what dogs are in your pedigree and what they have produced to ensure recessive and dominant faults & virtues so that you have an idea where each came from and who carries it. It is a process of elimination. One wishes in his mating to secure and retain the desirable characteristics, and it is easily demonstrated that this can best be accomplished by inbreeding and, to a lesser degree by line-breeding. It is also easy to show that, by using the same methods of breeding, the lowest intensity of undesirable characteristics is attainable. Results are entirely dependent upon "Selection" Genetically Dominant and Recessive Traits Dominant Recessive Long Head**************************Short Head Large Or Long ears**********Small or Short ears Low set ears******************High set ears Wide ear leather**************Narrow ear leather Coarse skull*******************Fine skull Short foreface*****************Long foreface Erect ears ********************Drop of tipped ears Dark eye***********************Light eye Normal eye ********************Large bulging eyes Brown eye*********************Blue eye Wire, short or curly coat ******Smooth long or straight coat Poor lay back ******************Good lay back Poorly angulated stifle********Well angulated stifle High set tail********************Low set tail Heavy bone********************Light Bone Deep chest********************Shallow chest Straight topline****************Sway back Good spring of rib*************Poor spring of rib Short stifle**********************Long stifle Light pigment******************Dark pigment Normal hearing****************Deafness Good eyesight*****************Night blindness Good eye pigment************Wall eyes Self-color***********************Parti-Color Black nose*********************Dudley nose Good mouth********************Overshot or undershot Normal palate******************Cleft palate Normal lip**********************Hair lip Straight tail***********************Kinked or bent tail